1. ## Circuit Help

I'm working with this circuit.
http://www.aaroncake.net/circuits/stepper.htm
To make it step am I supposed to apply 12 volts to the step line between 3 and 13?
Does this look like a pretty good circuit to be learning from?

2. hmm, really odd, pin 3 and 13 are indeed marked as "step", but the connections are
not labelled in the chip, so i don't know what they do.

just a few observations:
-you will need motors with a tap in the middle of each coil (i.e: 6 wire step motors,
while many (most?) step motors have only 4 wires.
-the S1 switch is only connected to inputs, so that wire will work as an antenna if
it's in the middle of the switch (i.e: rattle between + and - at a few MHz), tho the
rest of the electronics may take care of this, it's still better to avoid.
A more conventional way is to connect the input via a (10k) resistor to +12V and
then just a single switch to pull it down to 0V. (i.e: switch open: +12V.
switch closed: 0V)
-this circuit cycles through the 4 possible motor stages, but there is no reset, so you
(or the computer that is generating the steps does not know what the initial stage is)

What are you trying to do?
Do you want to drive the step motor from a printer port of a computer?
What kind of step motor do you have ?

jaap.

3. That is what it shows.

Here is a data sheet on the Fairchild CD4027

Pins 3 and 13 are the clock lines for each flip-flop.

DC

4. every time the "step"wire changes from 0V to 12V it will do a single step.

5. I'm working with the parallel port and visual basic. Electronics are a new subject to me. I have a breakout board with led's and I'm using visual basic to understand the output of the parallel port.
I've assembled that circuit on a breadboard with led's instead of a motor to see if I can get some output. So far no luck.

6. Ty connecting the "step" wire to +12V using a 10k (or similar) resistor, and then use a wire to
conenct it to 0V (at the same time) to generate the step pulses.

do any of the LED's light up ?

http://jwstolk.xs4all.nl/i/proptotyp...tor_driver.jpg

7. This was posted in another thread a few days ago. It gives a decent tutorial on using Qbasic and the parallel port as a control means.

Bits to Bytes

The output of most parallel ports are 5v, not 12v. I doubt this will work to trigger this circuit.

If you are completing the circuit with the transistors installed and still driving LED's. I would guess the LED's could be blown unless you put a 2K resistor in line with it. No need for the transistors. You should be able to connect the 2K resistors(in place of the 1K resistors) to the LED's anode (longer lead) and the LED's cathode(by the flat side of the case, shorter lead) to ground in place of the stepper motors. Using 4 LED's, with one at each resistor simulating the stepper phases.

This same circuit could be created using similar TTL IC's instead of the CMOS so it could operate on 5v. The resistor values would be cut in half too.

DC

8. This is generally the same circuit as the discrete board on my wedsite: http://pminmo.com/discrete/discrete.htm

9. Originally Posted by Shanghyd
I'm working with the parallel port and visual basic. Electronics are a new subject to me. I have a breakout board with led's and I'm using visual basic to understand the output of the parallel port.
I've assembled that circuit on a breadboard with led's instead of a motor to see if I can get some output. So far no luck.
i have registerd for ICQ and we spend some time testing/debugging.
the non-working led's have been traced to a broken 4027 chip and the 4000's not being
able to drive the LED's directly. so things are on the move again :-)
jaap.

10. Hi all, are there any Australians on this site? Our local electronics mag publishes stepper motor controllers from time to time, and a similar circuit to the above is provided on their web site. http://www.siliconchip.com.au/cms/A_100994/article.html

Cheers
Happymacer